The "mixpict" primitive should work for this purpose:
void mixpict mat_map
7 white_mat black_mat grey matmap.pic picture.cal pic_u pic_v
You have to define the two materials "white_mat" and "black_mat" and you'll probably want to change the picture coordinate mapping to suit your needs, but you get the idea.
From: "Lars O. Grobe" <[email protected]>
Date: April 6, 2008 8:27:38 AM PDT
trying to optimize an existing model, I have a rather basic question.
I have a surface, which is composed of two materials. Imagine something like a checkerboard, two materials, just not with squares but irregular forms. I have images of that surface, and of course I could simply map a foto onto a white surface using colorpict and get something close to real.
Still, as I have not only color but two materials involved, I do not like that idea. I want to have different material properties, not only color variation.
So far the problem is solved using two cad geometrys, one for each material. This is extremely inefficent, it produces tons of polygones and problems.
What I need is to take a black white picture, map it onto my surface, and have the black be material a and the white be material b in radiance.
Is there a reasonable way to do that in Radiance?